Shares of Apple were off $5.70 to $138.02 on Nasdaq after AT&T, the exclusive service provider for iPhone, said it signed up 146,000 iPhone customers as subscribers in the first two days of iPhone sales, well below analyst estimates for sales.

Pacific Crest analyst Andy Hargreaves said that while iPhone sales figures for coming months would be more telling than the first few days, AT&T's number had disappointed investors as some analysts estimated sales north of 500,000.

Hargreaves had himself estimated 400,000 iPhone sales for the first two days, he said.

The difference (between sales and activations) is going to be what was sold on eBay or activations that didn't happen immediately. There were some problems with activations but from what we heard it was minimal, the analyst said.

Apple and AT&T had attracted long lines of gadget enthusiasts to their stores when the much-hyped iPhone first went on sale in the evening of June 29.